Mitra (s.l.) peregrinula Mayer, 1864

Sacchetti, Claudia, Landau, Bernard & Ávila, Sérgio P., 2023, The Lower Pliocene marine gastropods of Santa Maria Island, Azores: Taxonomy and palaeobiogeographic implications, Zootaxa 5295 (1), pp. 1-150 : 80-81

Mitra (s.l.) peregrinula Mayer, 1864 species inquirenda

Plate 5 K

* Mitra peregrinula Mayer 1864: 82 , pl. 7, fig. 61.

Type material. Single specimen height 5.5 mm, width 2.5 mm, Feteirinhas (= Ponta das Salinas), Santa Maria Island , Azores, Touril Complex , Lower Pliocene ; whereabouts unknown ( Beu 2017:165) .

Original description. “ Trotz ihrem übeln Erhaltungszustande, glaube ich diese minutiöse Art doch als neu beschreiben zu müssen, da ihre Stellung eine ganz sichere ist und sie nur wenige Verwandte besitzt. Sie gehört nämlich zur kleinen Gruppe Conelix und steht einzig der M. conica ( C. conicus Swains. ) nahe, zeichnet sich aber durch ihre Kleinheit, ihre noch kürzere Gestalt und ihre gedrängteren Spiralfurchen davor aus. Ich fand sie, wie so viele andere interessante Arten, im Kalktuff der Feiteirinhas [Despite its bad state of preservation, I think I have to describe this minute species as a new species, since its position is quite secure, and it has only a few relatives. It belongs to the small group of Conelix and it is only close to M. conica ( C. conicus Swains. ), but is characterized by its small size, it is even shorter shape and its more crowded spiral grooves. I found it, like so many other interesting species, in the tuff of Feiteirinhas.]” ( Mayer 1864: 82).

Latin description. “ Testa minuta , turbinato-conica-transversisulcata; spira acuta, medio valde producta, acutissima; anfractibus numerosis, angustissimis; ultimo basi attenuato; labro simplici; columella basi plicata.” ( Mayer 1864: 82).

Discussion. The type specimen was illustrated from the dorsal side only and shows a juvenile shell with a strongly coeloconoid pointed spire and a totally conic last whorl. Moreover, Mayer’s 1864 Latin description says that the columella has a single fold at the base, whereas mitrid gastropods have numerous columellar folds. We are not sure how to identify this specimen, but it might represent a very juvenile cone shell.

Distribution. Lower Pliocene: Atlantic, Santa Maria Island, Azores ( Mayer 1864).

Mitra (s.l.) sp.

Plate 5 L 1 -L 2

Santa Maria material examined. Maximum height 12.9 mm, width 7.0 mm. DBUA-F 1295-3 (1), Malbusca (east cave), Santa Maria Island, Azores, Touril Complex, Lower Pliocene.

Revised description. Shell small to medium sized, relatively solid, spire missing. Penultimate whorl low, depressed, convex with periphery at abapical suture (low spire may in accentuated by wear), suture moderately impressed, linear. Last whorl somewhat globose, broadly rounded, moderately constricted at base, siphonal fasciole not delimited from base. Sculpture limited to a few weak cords over fasciole. Aperture elongate, very narrow adapically, widening slightly mid-aperture; anal sinus very narrow; siphonal canal moderate length, open, shallowly notched. Outer lip simple, not thickened by varix, weakly convex at extremities, flattened mid-aperture. Columella bearing narrow callus rim, abapical half thickened, bearing four prominent, oblique folds.

Discussion. The columellar folds confirm taxonomic placement within the Mitridae . This species is represented by a single specimen with the apex missing and the last whorl abraded. We aren’t sure that the penultimate whorl is a low and rounded as it seems or this is a result of wear. If not due to wear, the species would have a very low spire. The last whorl is also unusually globose and constricted at the base compared to other mitrids. We await further material to better characterised this species.

Distribution. Lower Pliocene: Atlantic, Santa Maria Island, Azores (this paper).

Figures

PLATE 1. A. Danilia pterostomus (Bronn, 1861), height 5.0 mm, width 4.0 mm, Forno da Cré (figure taken from Bronn in Hartung, 1861, pl. 19, fig. 2). B1-B2. Emarginula octaviana Coen, 1939, DBUA-F 487-1, height 1.8 mm, diameter 3.0 mm, Ponta do Castelo. C. Bolma cf. rugosa (Linné, 1767), DBUA-F 471-3, diameter 4.1 mm, Ponta do Castelo. D1-D5. Turbo hartungi Bronn 1861, DBUA-F 1295-1, height 9.0 mm, width 8.0 mm, Malbusca (east cave). E1-E3. Nerita cf. funata Dujardin, 1837, DBUA-F 917-1, height 4.0 mm, width 6.0 mm, Ponta do Castelo. F1-F2. Thericium crenulosum (Bronn, 1862), height 10.0 mm, width 6.0 mm, Ponta do Norte lighthouse, LNEG collection (unnumbered). G1-G2. Thericium hartungi (Mayer, 1862), height 29.0 mm, width 13.0 mm, Pinheiros (figure taken from Bronn in Reiss, 1862, pl. 1, fig. 11). H1-H2. Thericium incultum (Mayer, 1862), DBUA-F 1034-2, height 23.0 mm, width 10.0 mm, Macela viewpoint. I1-I2. Thericium incultum (Mayer, 1862), DBUA-F 1027-1, height 29.0 mm, width 11.0 mm, Malbusca II. J1-J2, K1-K2. Bittium miradouroense nov. sp., Holotype DBUAF 1034-5, height 6.8 mm, width 1.9 mm (J); Paratype DBUA-F 1034-6(1), height 5.3 mm, width 1.9 mm (K), Macela viewpoint. L1-L2, M1-M2. Bittium nov. sp., DBUA-F 488-2, height 4.5 mm, width 1.8 mm (L), height 4.2 mm, width 1.7 mm (M), Ponta do Castelo.

PLATE 2. A1-A2. Bittium nanum (Mayer, 1864), DBUA-F 1296-2, height 4.9 mm, width 2.0 mm, Malbusca. B. Tenagodus (Tenagodus) obtusus (Schumacher, 1817), DBUA-F 1283-2, height 12.0 mm, width 11.0 mm, Ponta do Castelo. C. Epitonium sp., DBUA-F 931-1, height 4.0 mm, width 2.8 mm, Pedra-que-pica. D1-D3. Janthina krejcii, SMF10135a, height 25.0 mm, diameter 32.0 mm, Macela viewpoint (pictures from Beu, 2017, fig. 26). E1-E3. Janthina typica (Bronn, 1861), DBUA-F-428, height 19.0 mm, diameter 21.0 mm, Ponta do Castelo, (pictures from Beu, 2017, fig. 25). F.Cheilea equestris (Linnaeus, 1758), DBUA-F 1283-1, diameter 30.0 mm, Ponta do Castelo. G1-G3. Hipponix sulcatus (Borson, 1820), DBUA-F 937-1, height 5.3 mm, diameter 14.0 mm, Ponta do Castelo. H1-H2. Euspira atlantica (Mayer, 1862), height 16.0 mm, diameter 19.0 mm, Ponta do Norte lighthouse, LNEG collection (unnumbered). I. Triphorid s.l., DBUA-F 471-5, height 3.2 mm, width 1.3 mm, Ponta do Castelo. J1-J2. Cerithiopsis cf. tubercularis (Montagu, 1803), DBUA-F 1023-1, height 3.0 mm, width 1.2 mm, Ponta do Castelo. K. Petaloconchus intortus (Lamarck, 1818), DBUA-F 946-2, height 13.0 mm, width 6.0 mm, Ponta dos Cedros. L. Thylacodes arenarius (Linnaeus, 1758), DBUA-F 869-1, height 33.0 mm, width 24.0 mm, Ponta dos Cedros. M1-M3. Alvania cancellata (da Costa, 1778), DBUA-F 1296-3, height 4.0 mm, width 2.2 mm, Malbusca.

PLATE 5. A1-A2. Tritia atlantica (Mayer, 1862), DBUA-F 1295-2, height 13.0 mm, width 6.5 mm, Malbusca (east cave). B1-B2 C1-C2. Tritia serraticosta (Ĥrnes, 1852), DBUA-F 1292-A, height 6.2 mm, width 4.1 mm (B); height 8.1 mm, width 4.2 mm (C), Macela viewpoint. D. Tritia vetulum (Mayer, 1862), height 12.0 mm, width 6.0 mm, Pinheiros (figure taken from Bronn in Reiss, 1862, pl. 1, fig. 5). E1-E2. Aplus sp., height 7.5 mm, width 4.0 mm, Ponta do Castelo, LNEG collection (unnumbered). F1- F2. Orania cf. bellardiana (Foresti, 1884), DBUA-F 828-2, height 17.0 mm, width 12.0 mm, Ponta dos Frades. G1-G2. Favartia suboblonga (d’Orbigny, 1852), DBUA-F 946-3, height 19.0 mm, width 10.0 mm, Ponta dos Cedros. H1-H2. Bellardithala obsoleta (Brocchi, 1814), DBUA-F 542-4, height 5.9 mm, width 2.0 mm, Ponta dos Frades. I1-I2 J. Cancilla volvaria (Bronn, 1862), DBUA-F 937-2, height 10.9 mm, width 4.8 mm (I), Ponta do Castelo; height 15.5 mm, width 5.5 mm (J), Pinheiros (figure taken from Bronn in Reiss, 1862, pl. 1, fig. 4). K. Mitra (s.l.) peregrinula Mayer, 1864 species inquirenda, height 5.5 mm, width 2.5 mm, Feteirinhas (= Ponta das Salinas) (figure taken from Mayer, 1864, pl. 7, fig. 61). L1-L2. Mitra (s.l.) sp., DBUA-F 1295-3, height 12.9 mm, width 7.0 mm, Malbusca (east cave). M. Africonus trochilus (Mayer, 1864), length 16.0 mm, width 9.0 mm (incomplete spire fragment), Pinheiros, (figure taken from Mayer, 1864, pl. 7, fig. 60). N1-N2. Lautoconus cf. anomalomamillus (Sacco, 1893), DBUA-F 924-1, height 22.0 mm, width 11.0 mm, Malbusca. O. Plagioconus sp., height 35.5 mm, width 16.0 mm, unknown locality, LNEG collection (unnumbered). P1-P2 Q. Stephanoconus candidatus (Mayer, 1862), DBUA-F 913, diameter 19.0 mm (apical fragment of juvenile), Ponta dos Frades (P); diameter 40.0 mm, height 22.0 mm (incomplete spire fragment), Pinheiros (figure taken from Bronn in Reiss, pl. 1, fig. 1).